Last year weather led to a pulse of increased volume being fed into the sea ice system, since then we have seen this pulse being severely reduced. Now much of the increased extent of older ice (multi-year ice or MYI) in the Central Arctic has been transported out into Beaufort and is currently making its way into Chukchi. What does this mean for the coming melt season?
As posted in my February 2014 Update, the volume pulse from the muted 2013 melt season has been severely reduced, I think that this was largely due to a negative Pacific North American (PNA) like atmospheric set up, more here. This can be seen best by considering the difference in regional volumes between 2014 and 2013 for January and February, as shown in this copy of a graph from my February post.
From this it can clearly be seen that the overall (All PIOMAS domain) and Arctic Ocean volume increase between 2013 and 2014 was substantially reduced by February.
However this is not all that has happened, over the winter the increased amount of older multi year ice (MYI) caused by greater ice survival in 2013 has seen a massive movement into the Beaufort Sea and onwards towards the Chukchi Sea.
A similar event occurred over the winter of 2010, and was a significant player in the 2010 volume loss event as discussed here. The following animated gif uses images from the Drift Age Model (DAM) provided by Fowler/Maslanik/Tschudi, available at ftp://ccar.colorado.edu/pub/tschudi/iceage/gifs/ .
Starting from week 45 in 2009 it can be seen how there was a substantial movement of older (especially red +5yr old) ice into Beaufort and Chukchi, by week 35 of 2010 most of this had melted out, leaving a remnant mass off the coast of Siberia. However in doing to it kept a spur of dispersed but notably persistent ice in the same region, e.g. Bremen (between 150 and 180 degE).
Thus the extent and area for 2010 were unremarkable, while the volume loss of that year is an outlier in the context of the post 2000 interannual volume changes (2007 and 2010 were about -2 sigma). By week 38, when ages were incremented upwards to account for the end of the melt season, how little of that MYI survived is seen below.
The effect of this loss of volume can be seen in the following animated gif showing ice thickness in February, whilst there is an overall thinning, both 2007 and 2010 show marked decreases in thickness.
This decrease of thickness is even more striking in the plots of PIOMAS thickness provided by the Polar Science Centre. Where 2010 ushers in a step break from the preceding years.
Now over the winter of 2013/14 a similar movement of MYI has happened into Beaufort and the eastern Chukchi Sea.
Comparing the most recent plot for 2014, week 13, with that for week 13 of 2010 shows that whilst the movement has not progressed as far (I don't think the Beaufort Gyre has been as vigorous as in 2010) the extent of ice seems to be much greater. As we move into the summer (it is only April now) more of this will be transported towards the East Siberian Sea.
This suggests to me that while this melt season will see probably a large volume loss as this older thicker ice is thinned and subjected to lateral melt, a total melt out in Beaufort, Chukchi, and possibly as far as the East Siberian Sea, is looking unlikely. I suspect we may see persistent low concentration ice in those regions by late summer. NSIDC seem to be of a similar mind, but don't consider the volume issue.